Safety casing head



C. B. REYNOLDS SAFETY CAS Get w, 3.9330

ING HEAD Filed Jan. 30, 1929 Patented Get. 10, 1933 UNITED STATES PATENT OFFICE 6 'blaims.

This invention relates to deep well apparatus, and has for an object the provision of a practical device which may be applied to a well casing preferably adjacent the upper end thereof, and which, in the event of an impending blowout, will form a closure between the well casing and the drill stem, to prevent the escape of gas or oil.

It frequently occurs during the process of drilling an oil or gas well, that when the drill penetrates a subterranean chamber wherein gas or oil, or both, are contained under very high pressure, this pressure will result in forcing the gas or oil upwards through the casing, carrying with it not only the circulation fluid with which the casing is filled, but frequently the drilling tools as well. This is termed a blow-out and is apt to cause considerable damage to both life and property. It frequently occurs that the pressure is so great that not only are the drilling tools carried from the well, but also the casing itself, motion of the casing starting after the contents of the casing have attained considerable velocity. Furthermore, the entire contents of the casing such as oil and gas, sand, circulation fluid, and the drilling tools, are frequently driven from the well with such Velocity that they destroy the drilling rig and adjacent buildings and machinery. Obviously, there is imminent danger at such a time, of fire and loss of life.

An object of my invention therefore, is the provision of apparatus for the prevention of such blow-outs;

A more detailed object is the provision of a blow-out preventer in the form of a housing adapted to be secured to the well casing preferably adjacent the upper end thereof, and having slidably mounted therein, a plurality of blocks or gates which may be advanced whenever desired, to engage the drill stem or whatever other rod-like structure may be extending through the housing, and form a seal to prevent the escape of fluids therepast.

A further object is the provision of a control device as described, in which the gates are so designed that they will grip the drill stem .with such force that liability ofthe drill stem slipping after being so gripped, is reduced to a minimum. Furthermore, the blocks are so designed that the force exerted thereby against the drill stem, is directly proportional to the upward pressure exerted by the circulation fluid and by the rod itself against the blocks. Consequently, the greater the pressure of the fluids inside the well casing, the greater the pressure exerted by the blocks against the drill stem will be.

A further object is the provision of-a control device as described, which may be controlled from a remote point. scope of the invention to provide a plurality of controls so that it may be activated from any one of a number of points.

A still further object is the provision of a con trol device especially designed to be used in conjunction with the mud stripper disclosed in my previously issued Patent No. 1,521,390, issued December 30, 1924.

The invention possesses other objects and advantageous features, some of which, with those enumerated, will be set forth in the following description of the inventions particular embodiment which is illustratedin the drawing accompanying and forming a part of the specification.

Referring to the drawing:

Figure 1 is a vertical, medial sectional View of a control device embodying the principles of my invention, and mounted in operative position upon a well casing. a

Fig. 2 is a horizontal sectional view taken upon 30 the line 2-2 of Fig. 1, with the direction of view as indicated.

Fig. 3 is a vertical, medial sectional view of a safety sealing cap adapted to be employed with the control device of my invention. 95

Specifically describing the invention in its most practical embodiment of which I am at present aware, the control device comprises a tubular housing 6 having a flange 7- at the lower end thereof, through which bolts 8 or equivalent fastening means may be passed to secure the housing 6 to the housing 9 of my previously patented mud stripper indicated in its entirety at 11. The housing 9 'of the mud stripper 11, is adapted to be secured to the casing 12 of a well, preferably adjacent or at the upper end thereof with the drill stem 13 extending through the bore 14 of the housing 9 and the bore 16 of the housing 6.

A conical chamber 21 is provided in the housing 6 with the bore 16 extending axially through g the chamber 21, and with the smaller end of the chamber 21' uppermost. A plurality of gates or blocks 22 are slidably mounted within the chamber 21 each of these blocks having the configuration of a conical sector, with its inner face 23 concave and of radius coinciding with that of the rod 13. Each of the blocks 22 is provided with a dove-tail tongue 26 slidable within a complementary groove 27 in the outer conical wall of the chamber 21, so that the blocks are slidable 0 In fact, it is quite within the 60 are-also formed on the inner arcuate faces 23 of the blocks 22.

Each of the gates 22 has associated therewith, a piston 36 slidable within a complementary cylinder 37 formed in the housing 6 in parallelism 'with the adjacent portion of the wall of the chamber 21. The rod 38 is so connected to the associated block 22 that when the piston 36 is slid upwards and inwards, the gate 22 is forced into position to engage the rod 13. An annular steam chamber 39 communicates with all of the cylinders 37; and steam or other working fluid may be supplied to the steam chamber 39 through a conduit 41 controlled by a suitable valve 42. A

spring 43 under tension between the back of each piston 36 and a portion of the housing 6, normally retains each piston and block 22 in fully retracted position as indicated in the draw- Another portion of the safety device of my invention is a cap 46 threaded interiorly as at 47, to be received upon threads 48 formed upon the upper end of the housing 6. The upper end of the cap 46 is closed by a web 49 except where a hole 51 extends therethrough; and passage of I fluids through this hole 51 is controlled by a safety valve 52.

The method of operation of the control device described hereinabove, is substantially as follows:

When there are indications that a blow-out of the well is impending, the drilling operation isstopped so as to bring the drill stem 13 to rest. Then, the valve 42 is opened to supply steam under pressure to the steam chamber 39. It should be understood that my invention contemplates the provision of a plurality of the valves 42 disposed at various points so that should the blowout actually occur before the workmen have had the opportunity of opening any of the valves 42, the device may be activated from a remote point where danger to the operator is relatively small.

When the steam is introduced to the steam chamber 39, all the pistons 36 will be simultaneously forced upwards and inwards, forcing all the blocks 22 in similar motion until they engage the drill stem 13. It is apparent that this engagement with the drill stem 13 will serve to prevent subsequent flow of fluids from the casing 14, ex-

cept through the discharge pipe 56 which communicates with the interior of the casing below the housing 9.

Any tendency of the rod 13 to move upwards, will cause the teeth 33 to bite into the metal of the stem 13 and to produce a wedging action directly proportional to the upward force exerted upon the rod 13, tending to hold the rod motionless. The packings 32 will establish a fluid-tight seal between the blocks 22 and the rod 13, and

since when the blocks 22 are in engagement with the rod 13, they define a complete frustum of a cone, the base of which is larger than the smaller end of the chamber 21, a fluid-tight seal or plug will be thus provided, preventing escape of fluids from the upper end of the housing 6. This wedging action is'also produced against astationary rod 13 by upward pressure of fluid against the bottom of the blocks 22.

After a well has been once brought under control by the device, and in accordance with the method described, it is possible to relieve the pressure within the chamber 39 so that the drill stem 13 may be lowered or raised to dispose .one of the couplings between the blocks 22 and the upper end of the housing 6. The drill stem 13 should then be broken at this coupling, and the cap 46 attached to the upper end of the housing. It is obvious that if there is no drill stem 13 within the well at the time the blow-out starts, the cap 46 should be attached immediately.

It is to be understood that the details of the invention as herein disclosed, are subject to alteration within the spirit or scope of the appended claims.

I claim:

1. A control device for a well casing having a rod-like structure therein comprising a tubular housing adapted to be secured to the casing with said rod-like structure extending through the bore of the housing, a plurality of gates mounted in said housing for sliding movement in convergency with said rod-like structure, means for advancing said gates to engage the rod-like structure, and spring means urging said gates to retracted position.

2. A control device for a well casing having a rod-like structure therein comprising a tubular housing adapted to be secured to the casing with said rod-like structure extending through the bore of the housing, a plurality of gates mounted in said housing for sliding movement in convergency with said rod-like structure, the inner faces of said gates being complementary to said rodlike structure, means for advancing said gates to engage the rod-like structure, and spring means urging said gate to retracted position.

3. A control device for a well casing having a rod-like structure therein comprising a tubular housing adapted to be secured to the casing with said rod-like structure extending therethrough, said housing having a conical chamber therein with the bore of the housing extending through the chamber, a plurality of blocks slidable within said chamber, each of said blocks having the, configuration of a conical sector with its inner face concave and of radius coincident with that of the rod-like structure, the concave face of each of said blocks having a recess extending thereacross, an insert of resilient packing seated in each of said recesses, means for advancing the blocks to engage the rod-like structure, and spring means interposed between said advancing means and said housing to urge said blocks to retracted position.

4. A control device for a well casing having a rod-like structure therein comprising a tubular housing adapted to be secured to the casing with said rod-like structure extending therethrough, said housing having a conical chamber therein with the bore of the housing extending through the chamber and with the smaller end of the conical chamber uppermost, a plurality of blocks slidable within said chamber, each of said blocks having the configuration of a conical sector, a piston secured to each of said blocks and slidably mounted in a cylinder in said housing, and means for introducing fluid under pressure behind said pistons to slide the blocks upwards and inwards to engage the rod-like structure.

5. A control device for a well casing having a in parallelism with the wall of said chamber, and means for introducing fluid under pressure behind said pistons to slide the blocks upwards and inwards to engage the rod-like structure.

6. A control head for well casing having a taper bore converging axially upward in the direction opposite the well casing, said control head containing taper slips for engaging a drill string, and means comprising links and springs for separating said slips. I

CHARLES E. REYNOLDS. 

